The disclosed device relates to a hoist ring. More particularly it relates to a swiveling hoist ring that is typically used to lift very heavy equipment by cooperative attachment of the hoist ring to the equipment being lifted. Such hoist rings conventionally have a body portion that is placed in threaded engagement with the equipment being lifted using a bolt through a center aperture in the body portion. The body portion is then cooperatively engaged with two ends of a ring member which engages protruding flanges which are threaded into the sides of the body portion.
To date the lifting capacity of such devices has been limited to the strength of the engagement of the protruding flanges which are in threaded engagement into the body portion since the flanges are separate pieces from the body portion. Or in some cases the lift ring has bent ends that protrude into divots in the body portion which are then capped to hold the ring ends in the divot. This too limits the strength of the lifting device to the strength of ring at the bend and the parts engaging the ring ends with the body portion.
In the heavy equipment industry, there is a constant requirement to relocate equipment which weighs tons. Such equipment while being large and heavy, is frequently delicate due to the nature of the operation of the equipment when running. Laths, mills, tape mills, and other such equipment must operate to make products that have extremely small tolerances when in operation. However, the weight and bulk of heavy equipment naturally make it hard to handle.
As such, manufacturers and owners of such bulky and heavy machinery frequently provide lift points where the body of the machine being hoisted may be attached to a cooperating fastener to provide an attachment point for a crane or similar heavy lifting device. Conventionally, such attachments feature apertures extending into the body of the machine to be lifted, which can be engaged by shackles or lifting rings which are fitted with the proper cooperating attachment to thread into the various apertures for lifting.
Known as shackles, hoist rings, lifting eyes, and similar names, the devices generally follow the same use pattern and feature some sort of U-shaped ring attached at both ends to a centrally located body portion which is engaged may be engaged in turn with the machine to be lifted. Frequently the U-shaped ring is engaged with the body portion between the sides of the U-shaped ring in a manner to provide a swivel to the ring.
Such an engagement of the ends of the ring to allow for a swivel generally requires that the ends of the ring itself somehow engage the body portion themselves, or, be attached to the body portion by bolts or other attachments which engage through the U-shaped ring and with the body portion. However, this method of attachment of the ring to the body severely limits the load that the assembled hoist ring device may lift since the strength of the parts holding the body portion together in the attachment to the ring ends is a limiting factor. If the equipment weight exceeds the strength of the screws or bolts or other parts holding the ring ends in engagement with the body portion, a separation occurs and the equipment falls to the ground.
The device herein disclosed solves this connection problem by eliminating the fasteners or cooperative engagement of flanges used on other swivel style hoist rings to attach the U-shaped ring to the body. By eliminating the separate protruding flanges to engage the U-shaped ring, the fasteners and screws and pins that are used to assemble body to the flanges which engage the ring ends are eliminated. This allows for the provision of a direct engagement of the one piece U-shaped ring to a one piece unitary body portion having a protruding flange vastly improving the strength of the assembled hoist ring device.
U.S. Pat. No. 4,074,519 (Garrett) teaches a swivel shackle for lifting machinery. However, Garret requires the use of a two piece Y-shaped adapter which is bolted to the U-shaped ring and increases the number of parts required and the number of parts which can fail due to an indirect attachment of the U shaped ring to the body portion.
U.S. Pat. No. 5,248,176 (Fredriksson) discloses a swivel coupling device for coupling a load to a base member. However the strength of the Fredriksson device is limited by the need to bend the ends of the U-shaped ring and the use of a plurality of parts to form the body section which weakens the entire hoist ring.
U.S. Pat. No. 5,979,954 (Tsui) discloses a safety hoist ring for lifting heavy loads. Tsui however suffers from the inherent problem of other prior art in that the body portion is separate from a pin which must be inserted through the U-shaped ring and the body.
U.S. Pat. No. 5,634,734 (Schron) features a triangular shaped ring that engages with a multiple piece body section. However, the lifting capacity of Schron is limited by the fact that it requires a two piece body which is held together by a plurality of bolts. Other available prior art suffers from the same problems created with multiple piece body sections or ring sections.
Thus, there is a continuing need for improvement in hoist ring devices to overcome the weight lifting restrictions imposed by the need to assembly such devices from multiple parts which inhibit their strengths. Additionally, there is a need to alleviate the waste of time caused by assembly, lost parts, and potential failure due to overloading of such hoist ring devices.
Accordingly, it is the object of this invention claimed herein to provide a simplified hoist ring device that is provided as a unit and that requires no assembly by the user.
It is another object of this invention to provide a hoist ring that provides increased lifting capacity from the increased strength provided the unitary body engaged having protruding flanges that engage with a unitary structure ring member.
It is still another object of this invention provide a method of manufacture of a hoist ring that has a unitary body portion with protruding flanges which engage a unitary ring structure when fully assembled.
It is an additional object of this invention to provide a hoist ring that is easily attached to conventional hoist ring connection points on heavy machinery thus allowing it to be used in an installed base of such devices without having to alter them or the machinery being lifted.
Further objectives of this invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the current preferred embodiments of the invention without placing limitations thereon. This device and method of manufacture accordingly comprise the features of the construction, combination of elements, and arrangement of parts that will be exemplified in the construction hereinafter set forth in the specification, and the scope of the preferred embodiments of the invention will be indicated in the claims.